The present invention relates to a door structure of an automotive vehicle which is applicable to a side door or a back door of the vehicle.
Since a light-metal material, such as aluminum or aluminum alloy, is relatively light and low cost compared to steel or the like, a casting or hollow extrusion molding using this light-metal material has been generally used for the door structure.
In a case of the casting, there is an advantage in integrally forming of a member with reduced forming steps even if the member becomes rather complex in order to provide an attachment portion for another member or the like. However, there is a concern that a large-sized mold may be required to form plural parts in a single member, which may increase costs reversely, or the strength of the member may vary improperly because of its complex shape or the like.
In a case of the extrusion molding, meanwhile, there is an advantage in forming a member having proper strength with reduced costs because the extrusion molding has a high rigidity in its longitudinal direction (an extrusion direction) and also its width-directional strength is increased by forming a closed cross section which may be made easily. However, it has a disadvantage that its forming is limited to a straight forming manner.
That is, a member of the door structure, such as an outer panel or a guide rail, is generally configured, in a case in which the door is a side door, such that its front view is designed to be curved from perspectives of design property or functionality. Accordingly, in a case in which a door frame is composed only by frame members which are made by an extrusion molding process such that the frame members are configured to extend straightly in a longitudinal direction thereof, it is difficult to attach another member having its curved front view described above to this door frame, which may deteriorate precision and reliability of attachment.
Therefore, a door structure which is constituted by combining the extrusion molding and the casting has been recently proposed, in order to solve the above-described concerns of the extrusion molding and the casting, utilizing the above-described advantages of those, by UK Patent Application GB 2316431 A or Japanese Patent Laid-Open Publication No. 2005-041266.
The above-described first patent document discloses the door structure in which a door frame is constituted by hollow extrusion moldings (12, 16, 30, 34, 40) which are respectively formed in a straight shape, castings (18, 24) which are respectively provided with projections (44) integrally formed at each end portion thereof, and nodes (41a-41c) which are respectively made by the casting process. This door structure is configured such that the projections (44) are pressed into hollow portions of the extrusion moldings, thereby joining the extrusion moldings and the castings together, and also the nodes (41a-41c) are inserted into the hollow portion of the extrusion moldings, thereby joining the extrusion moldings together via the nodes. However, since the door structure of the first patent document is configured such that the plural frames are formed in a frame shape so as to create a single face, without being arranged on an outward side as well as on an inward side, in a vehicle width direction, of the door structure, there is room for improvement from viewpoints of the safety against a vehicle collision, such as a side collision.
Further, the above-described second patent document discloses the door structure for a vehicle which comprises a door inner (18) which is made of aluminum casting and forms a skeleton of the door and a beltline reinforcement (14) which is made of aluminum extrusion molding and extends in a vehicle longitudinal direction along a beltline portion of the door. This beltline reinforcement (14) is fixed in a state in which its front end portion contacts a rear wall portion of the door inner (18) or is positioned closely to the rear wall portion of the door inner (18). In the case of the door structure for the vehicle of the above-described second patent document, there is only the single reinforcement arranged in the vehicle width direction and also the door inner (18) and the beltline reinforcement (14) are not joined by engagement (insertion). Therefore, there is room for improvement from the viewpoints of the safety against the vehicle collision, such as the side collision, as well as the door structure of the first patent document.
Meanwhile, in a manufacturing process of the door, a module (auxiliary device) positioned inside the door, such as a window regulator, is generally attached from a vehicle inward side through an opening formed at a center of the door. Alternatively, after an inner panel and an outer panel have been assembled together, the module is inserted into a door body from above, passing through a door-window insertion hole which is provided at an upper portion of the door body so as to allow a door window to get in or out, and then attached to its attachment position. Accordingly, it is difficult to arrange the internal module at a gap between door frames of the door structure and smoothly attach this internal module to the frames, so that there is a concern that the assemblability (productivity) may be inferior.
Moreover, in this case, a space for inserting the internal module into the door body and moving it to its attachment position or a work space for the attachment are required to be provided, which may improperly influence a shape of a cross section of the door outer panel and the like. Consequently, it is difficult to secure a superior door design. The above-described patent documents refer to nothing about an attaching step or position of the internal module to the door frames. Thus, there is still room for improvement on the above-described problems or concerns regarding the sessemblability and the design property of the door outer panel.